Invasion of tissue by tumor cells is an essential component of metastasis. In the past year we have developed a project to define the role of cell motility in the invasive process and the ultimate localization of metastatic tumors. A supplement to the NFCR is presently supporting the transfection of metastiatic breast tumor cells with formyl peptide chemoattractant receptor. The cells will be sorted by flow cytometry and selected on the basis of motility and invasion assays. The localization of metastases of the cell sublines will be characterized in animal models.